<template>
	<ul class="list test">
		<li 
			class="item" 
			v-for="item of letters" 
			:key="item"
			:ref='item'
			@click="handleLetterClick"
			@touchstart.prevent="handleTouchStart"
			@touchmove="handleTouchMove"
			@touchend="handleTouchEnd"
		>
			{{item}}
		</li>
	</ul>
</template>

<script>

export default {
	name: 'CityAlphabet',
	props: {
		cities: Object
	},
	data () { 
		return {
			touchStatus: false,
			startY: 0,
			timer: null
		}
	},
	updated (){
		this.startY = this.$refs['A'][0].offsetTop
	},
	computed: {
		letters () {
			const letters = []
			for (let i in this.cities) {
				letters.push(i)
			}
			return letters
			// ['A','B'...]
		}
	},
	methods: {
		handleLetterClick(e) {
			this.$emit('change',e.target.innerText)
		},
		handleTouchStart() {
			this.touchStatus = true
		},
		handleTouchMove (e) {
			if (this.touchStatus) {
				if(this.timer){
					clearTimeout(this.timer)
				}
				this.timer = setTimeout (() => {
					const touchY = e.touches[0].clientY - 79
					const index = Math.floor((touchY - this.startY) / 20)
					if (index >= 0 && index < this.letters.length) {
						this.$emit('change',this.letters[index])
					}
				},16)
			}
		},
		handleTouchEnd () {
			this.touchStatus = false
		}
	}
}

// $(function(){
// 	$('.test li').click(function(){
// 		$('.test li').not(this).css('fontWeight', 'normal');
// 		$(this).css('fontWeight', 'bold')
// 	})
// })

</script>

<style lang="stylus" scoped>
	@import '~styles/varibles.styl'
	.list
		display: flex
		flex-direction: column
		justify-content: center
		position: absolute
		top: 1.58rem
		right: 0
		bottom: 0
		width: .4rem
		.item
			text-align: center
			line-height: .4rem
			color: $bgColor
</style>